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Structural Study of P4W14O50, a New Odd Member in the Series (PO2)4(WO3)2m

1996; Elsevier BV; Volume: 122; Issue: 2 Linguagem: Inglês

10.1006/jssc.1996.0114

1095-726X

Pascal Roussel, Ph. Labbé, D. Groult, B. Domengès, H. Leligny, D. Grebille,

Polyoxometalates: Synthesis and Applications

Single crystals of the odd memberm= 7 of the series of low dimensional tungsten bronzes (PO2)4(WO3)2mhave been grown by means of chemical vapor transport technique. The structure has been solved from X-ray diffraction data in the monoclinic space groupP21/nwith the lattice parametersa= 5.291(1) Å,b= 6.557(2) Å,c= 26.654(8) Å, and β = 90.19°. In contrast to them= 5 compound whose structure has been found as corresponding to the regular intergrowth of the two even membersm= 4 andm= 6, them= 7 compound can be considered as a pure phase whose structure is similar to that ofm= 4, 6, or 8 members. It can indeed be described by a stacking of WO6octahedral slabs of ReO3-type, all of the same thickness, connected through PO4tetrahedra. The difference about the crystal symmetry between the termsm= 7 andm= 6 is discussed in terms of tilting of WO6octahedra.